JPH03208019A - Production of liquid crystal display device - Google Patents

Abstract

PURPOSE:To lessen the generation of static electricity and to prevent the electrostatic breakdown of thin-film transistors (TFTs) by executing a rubbing treatment in a steam atmosphere. CONSTITUTION:A TFT substrate 1 provided with the TFTs in a matrix shape is mounted on a movable table 2 and the rubbing treatment is executed while steam 4 is blown to the periphery of the contact part of a rubbing treating roller 3 at the time of forming an oriented film on the substrate 1. The steam humidity is preferably 70 to 90%. The electrostatic charge quantity is high if the humidity is below 70%. Water drops stick to the rubbing treating part and the stability of the rubbing treatment is inferior if the humidity exceeds 90%. The more preferably humidity is 75 to 85%. The charge quantity at such humidity is about 0.02 to 0.03kV and can be decreased to the lower value of about 1/3 to 1/15 the dielectric strength of the TFTs.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing an active matrix liquid crystal display (LCD) using a thin film transistor (TPT);
In particular, it concerns the rubbing treatment method for the alignment film. [Prior Art] As is well known, a liquid crystal display element consists of a TPT substrate and an alignment film provided thereon. A liquid crystal material interposed between the alignment film and one of the alignment films. Consists of a common electrode substrate.

Then, the alignment film provided on the TPT substrate is printed and burnt on the TPT substrate, and then a rubbing process is performed to make the orientation constant.

This rubbing process is performed by rubbing the surface of the alignment film in one direction with a cloth or the like. however,
This is because the alignment film is an insulating organic thin film. Static electricity is likely to be generated during this rubbing process. and. This static electricity is
This is a major cause of electrostatic damage to thin film transistors (TPT).

In addition. Generally, the withstand voltage of TPT against static electricity is 0.1 to 0.
, 3KV, high voltage TPT'? ' is also about 0.4KV.

Therefore. Conventionally, a method has been proposed in which the gate electrode terminal group and one source electrode terminal group of the TPT are short-circuited around the entire circumference (guard frame method) and the above-mentioned rubbing is performed (Japanese Unexamined Patent Publication No. 61-12268, (Refer to Japanese Patent Publication No. 1983-59475).

[Problem to be solved]

However, this method uses COG (chtp
Onglass type liquid crystal display elements have the following problems. Note that the GOG type here refers to the above-mentioned LCD using the above-mentioned TPT, and a gate land portion in which the terminal groups of each of these electrodes are concentrated. Refers to a type of liquid crystal display element in which a source land portion is provided on a glass substrate. A driving IC element for controlling the operation of the liquid crystal display element is mounted on this land portion.

That is, in the case of the above COG type, the TP of the IC driver
Layout constraints on T-board. For example, when ICs are arranged in a U-shape in at least three directions, it is not possible to adopt the guard frame method of short-circuiting both terminal groups around the entire circumference as described above.

Also, regardless of the guard frame method. In order to equalize the potential between the TPT elements, for example, there is a method of connecting the COG land portions. However, if the wiring is not cut between these lands using a means such as a laser after LCD processing, the LCD inspection will fail. It is not possible to carry out IC mounting, IC operation inspection, etc. Additionally, cutting wires between lands is a big burden. Productivity is very low.

The present invention has been developed in view of these problems. Reduces the amount of static electricity and does not cause static damage to TPT. The present invention aims to provide a method for manufacturing a liquid crystal display device.

[Means for solving problems]

In the present invention, an alignment film is placed on a substrate on which Fj film transistors are provided in a matrix. The alignment is performed by rubbing the surface of the alignment film. The method of manufacturing a liquid crystal display device is characterized in that the rubbing treatment is performed in a water vapor atmosphere.

The above water vapor is applied to the rubbed area. It takes effect by spraying water vapor locally. That is. When rubbing the alignment film surface using a rubbing device such as a rubbing roller. Water and air is sprayed around the contact area between the rubbing treatment tool and the alignment film. This water vapor is supplied using, for example, a humidifier and pipes.

Moreover, it is preferable that the humidity of the steam atmosphere is 70 to 90%. If it is less than 70%, the amount of static electricity is high. On the other hand, if it exceeds 90%, water vapor droplets will adhere to the rubbed cloth, causing a pile "gathering phenomenon" and resulting in poor stability of the rubbing treatment.

In addition. At 70-75%, there is variation in TPT breakdown voltage. Considering that it is expected that TPT may be damaged by static electricity due to variations in humidity, and that the above-mentioned "clumping phenomenon" of piles occurs. The most preferable humidity is 75-85%. Also. The rubbing process. This is done using a roller wrapped around a rubbed cloth. Rayon and nylon are used as rubbing-treated cloth. The above-mentioned alignment film, which is made of polyester or the like, consists of TFTs formed in a matrix on a substrate.
Print coating on top. It's being incinerated.

Note that an upper alignment film and a substrate are placed on the alignment film that has been oriented by the rubbing process at a predetermined distance using a spacer, and a liquid crystal material is injected between both alignment films to form a liquid crystal display device. .

Also. The present invention can be applied not only to the GOG type but also to other types of liquid crystal display devices. C Effect] In the present invention, the rubbing treatment is performed in a steam atmosphere.

As a result, water vapor creates a high humidity environment near the rubbing process. The amount of static electricity can be extremely reduced. for example. Humidity of water vapor atmosphere is 75-85%
In this case, the amount of charge generated in the rubbing process is 0.
．． Approximately 02 to 0.03 KV, 1/3 to 1/3 of TPT breakdown voltage
This can be reduced to as low as one-fifth. Therefore, according to the present invention. Reduces the amount of static electricity and does not cause static damage to TPT. A method for manufacturing a liquid crystal display device can be provided.

〔Example〕

First Embodiment A method of manufacturing a liquid crystal display device according to an embodiment of the present invention will be explained with reference to FIGS. 1 to 3.

When performing the rubbing process. As shown in FIGS. 1 and 2, the TPT substrate 1 is placed on the movable table 2. Also. A rubbing roller 3 is arranged so as to be in contact with the alignment film on the upper surface of the TPT substrate 1. Also, water vapor 4 is sprayed around the contact area between the roller 3 and the TFTMi1. Then, the rubbing process is performed by the rollers 3 while moving the movable table 2 from side to side. A cross-sectional view of the TPT substrate 1 above is. Typically. As shown in Fig. 3, it consists of a glass substrate 11 and TPTIOs arranged in a matrix on the glass substrate 11. The TPTIO includes a gate line 12, a gate vA rim 13 coated thereon, and .
On top of that, (a-Si)14, Cn+
)15 and. Source line 16, drain 17 and pixel electrode (
IT○)18 and more. The above n+ is for establishing an oak Q7 contact between the a-Sil4 and the source 16 and drain 17. and. An alignment film is placed on top of these (l illustration not shown).

The above-mentioned alignment film was formed by printing a polyimide resin liquid on the glass substrate 11 and performing tri-baking.

Then, the TPT substrate 1 was cleaned and subjected to a rubbing treatment.

Also. Movable table 2 is. It has a rotating wheel on its lower surface, and is movable in the left and right direction by a cylinder 22. On the other hand, roller 3. It is located at a position where it can come into contact with the surface of the TFT substrate l on the movable table 2, and is also connected to the motor 31. Additionally, a rubbing cloth is wrapped around the surface of the roller 3. Also, near roller 3. A spray port 42 of a water vapor supply pipe 4I is provided. The supply pipe 41 is
It is connected to a humidifier 40. A drain is provided in the middle of the supply vibrator 41 to prevent water from accumulating.

Next, during the rubbing process, the movable table 2 is moved left and right as described above. Due to this. The TPT substrate 1 placed thereon also moves left and right.

direction. The roller 3 rotates in the direction shown by the arrow in FIG. 1, and rubs the alignment film on the TFT substrate 1.

Therefore, the rubbing process involves the unidirectional rotation of the roller 3 and the TFT.
This is done by moving relative to the left and right movement of base 11. Also. During the above-mentioned rubbing process, a large amount of water vapor 4 is sprayed from the spray port 42 of the aquatic weed supply pipe 41 around the contact area between the roller 3 and the alignment film. Due to this. A water vapor atmosphere is formed. Rubbing treatment is performed in a steam atmosphere. In this example, the humidity of the steam atmosphere is 75 to 85%.
And so. The above rubbing process takes approximately 5 seconds each time.
The water vapor supply time was approximately 20 seconds while the movable table was moving. After the rubbing process, the TPT base Fi1 is taken out from the movable table 2 and a liquid crystal display device is assembled.

Note that the above rubbing treatment is for the purpose of maintaining the above humidity. It is preferable to surround the openings of the roller 3 and the supply pipe 41 with a box.

As above. According to this example, a high humidity environment is created by water vapor near the rubbing process, and the amount of static electricity is extremely small. Therefore, there is no risk of TPT being damaged by static electricity during the rubbing process.

Second Example During the rubbing treatment in the first example, the relationship between the humidity of aquatic plants and the amount of electrostatic charge near the rubbing treatment was measured.

The results are shown in Table 1. As can be seen from Table I, the amount of electrostatic charge decreases as the humidity increases. Also. Generally, TPT has a static electricity withstand voltage of 0.1 to 0.3 KV, so it can be seen that the rubbing treatment should be performed at a humidity of 70% or more, more preferably 75% or more, depending on the TPT's withstand voltage. In addition. Although the above example was shown for a TPT liquid crystal display element, it can also be applied to rubbing treatment for other liquid crystal display elements.

Also. The present invention provides the following advantages:
It can also be applied to the polarizing plate pasting process. In this pasting process. When peeling off the polarizing plate and its protective sheet. In particular, a lot of static electricity is generated.

Therefore. This pasting process also uses an aquatic plant atmosphere. It is possible to reduce the generation of static electricity and prevent static electricity damage to TPT.

[Brief explanation of drawings]

Figures 1 to 3 show the state during the rubbing process in the first embodiment, and Figure 1 is a side view of the rubbing processing apparatus,
The figure is a plan view of Figure 1. FIG. 3 is a cross-sectional view of the TPT substrate. 1. 1 0. 2. 3. 4. 40. TPT substrate TPT, movable table, roller, steam humidifier, 3 Fig. 1

Claims (1)

[Claims] On a substrate on which thin film transistors are provided in a matrix,
A method for manufacturing a liquid crystal display device, in which an alignment film is placed and the surface of the alignment film is subjected to a rubbing treatment to achieve alignment, wherein the rubbing treatment is performed in a water vapor atmosphere. Method.